diff options
Diffstat (limited to 'llvm')
| -rw-r--r-- | llvm/lib/Transforms/Scalar/IndVarSimplify.cpp | 17 | ||||
| -rw-r--r-- | llvm/test/Transforms/IndVarSimplify/iv-widen.ll | 39 |
2 files changed, 51 insertions, 5 deletions
diff --git a/llvm/lib/Transforms/Scalar/IndVarSimplify.cpp b/llvm/lib/Transforms/Scalar/IndVarSimplify.cpp index c291f68bd63..c992f8c12a6 100644 --- a/llvm/lib/Transforms/Scalar/IndVarSimplify.cpp +++ b/llvm/lib/Transforms/Scalar/IndVarSimplify.cpp @@ -897,15 +897,24 @@ const SCEVAddRecExpr *WidenIV::GetWideRecurrence(Instruction *NarrowUse) { return AddRec; } +/// This IV user cannot be widen. Replace this use of the original narrow IV +/// with a truncation of the new wide IV to isolate and eliminate the narrow IV. +static void truncateIVUse(NarrowIVDefUse DU, DominatorTree *DT) { + IRBuilder<> Builder(getInsertPointForUses(DU.NarrowUse, DU.NarrowDef, DT)); + Value *Trunc = Builder.CreateTrunc(DU.WideDef, DU.NarrowDef->getType()); + DU.NarrowUse->replaceUsesOfWith(DU.NarrowDef, Trunc); +} + /// WidenIVUse - Determine whether an individual user of the narrow IV can be /// widened. If so, return the wide clone of the user. Instruction *WidenIV::WidenIVUse(NarrowIVDefUse DU, SCEVExpander &Rewriter) { // Stop traversing the def-use chain at inner-loop phis or post-loop phis. if (isa<PHINode>(DU.NarrowUse) && - LI->getLoopFor(DU.NarrowUse->getParent()) != L) + LI->getLoopFor(DU.NarrowUse->getParent()) != L) { + truncateIVUse(DU, DT); return 0; - + } // Our raison d'etre! Eliminate sign and zero extension. if (IsSigned ? isa<SExtInst>(DU.NarrowUse) : isa<ZExtInst>(DU.NarrowUse)) { Value *NewDef = DU.WideDef; @@ -953,9 +962,7 @@ Instruction *WidenIV::WidenIVUse(NarrowIVDefUse DU, SCEVExpander &Rewriter) { // This user does not evaluate to a recurence after widening, so don't // follow it. Instead insert a Trunc to kill off the original use, // eventually isolating the original narrow IV so it can be removed. - IRBuilder<> Builder(getInsertPointForUses(DU.NarrowUse, DU.NarrowDef, DT)); - Value *Trunc = Builder.CreateTrunc(DU.WideDef, DU.NarrowDef->getType()); - DU.NarrowUse->replaceUsesOfWith(DU.NarrowDef, Trunc); + truncateIVUse(DU, DT); return 0; } // Assume block terminators cannot evaluate to a recurrence. We can't to diff --git a/llvm/test/Transforms/IndVarSimplify/iv-widen.ll b/llvm/test/Transforms/IndVarSimplify/iv-widen.ll new file mode 100644 index 00000000000..12067ab6fe8 --- /dev/null +++ b/llvm/test/Transforms/IndVarSimplify/iv-widen.ll @@ -0,0 +1,39 @@ +; RUN: opt < %s -indvars -S | FileCheck %s + +target triple = "x86_64-apple-darwin" + +; CHECK-LABEL: @sloop +; CHECK-LABEL: B18: +; Only one phi now. +; CHECK: phi +; CHECK-NOT: phi +; We now get 2 trunc, one for the gep and one for the lcssa phi. +; CHECK: trunc i64 %indvars.iv to i32 +; CHECK: trunc i64 %indvars.iv to i32 +; CHECK-LABEL: B24: +define void @sloop(i32* %a) { +Prologue: + br i1 undef, label %B18, label %B6 + +B18: ; preds = %B24, %Prologue + %.02 = phi i32 [ 0, %Prologue ], [ %tmp33, %B24 ] + %tmp23 = zext i32 %.02 to i64 + %tmp33 = add i32 %.02, 1 + %o = getelementptr i32* %a, i32 %.02 + %v = load i32* %o + %t = icmp eq i32 %v, 0 + br i1 %t, label %exit24, label %B24 + +B24: ; preds = %B18 + %t2 = icmp eq i32 %tmp33, 20 + br i1 %t2, label %B6, label %B18 + +B6: ; preds = %Prologue + ret void + +exit24: ; preds = %B18 + call void @dummy(i32 %.02) + unreachable +} + +declare void @dummy(i32) |
